Remove RefCountedGarbageCollected<> GC plugin handling.

tools/clang/blink_gc_plugin/RecordInfo.cpp

Index: tools/clang/blink_gc_plugin/RecordInfo.cpp
diff --git a/tools/clang/blink_gc_plugin/RecordInfo.cpp b/tools/clang/blink_gc_plugin/RecordInfo.cpp
index 2f17234830a92d6916a2a9eebb752dd03c75b95a..f0e2ade715bb63255b5d0e34eaf54097de1c28b7 100644
--- a/tools/clang/blink_gc_plugin/RecordInfo.cpp
+++ b/tools/clang/blink_gc_plugin/RecordInfo.cpp
@@ -186,16 +186,6 @@ bool RecordInfo::IsEagerlyFinalized() {
   return is_eagerly_finalized_;
 }
 
-bool RecordInfo::IsGCRefCounted() {
-  if (!IsGCDerived())
-    return false;
-  for (const auto& gc_base : gc_base_names_) {
-    if (Config::IsGCRefCountedBase(gc_base))
-      return true;
-  }
-  return false;
-}
-
 bool RecordInfo::HasDefinition() {
   return record_->hasDefinition();
 }